Update codecov/codecov-action action to v4

| datasource  | package                | from   | to     |
| ----------- | ---------------------- | ------ | ------ |
| github-tags | codecov/codecov-action | v3.1.1 | v4.0.0 |

Author: renovate[bot]

.github/workflows/phpunit.yml

@@ -165,4 +165,4 @@ jobs:
         run: "make phpunit PHPUNIT_FLAGS='--coverage-text --coverage-clover=coverage.xml'"
 
       - name: "Upload Coverage"
-        uses: "codecov/codecov-action@v3.1.1"
+        uses: "codecov/codecov-action@v4.0.0"